Corrosion evaluation of artificially aged 6 wt-% tin bronze

Abstract

T his study concerns the corrosion behaviour of wrought 94 wt-%Cu-6 wt-%Sn (B6) bronze, G. BRUNOROwhose composition is similar to materials used for outdoor bronze artefacts. In order to G. LAGUZZIinvestigate the influence of the composition and microstructure on bronze corrosion pro-L. LUVIDI cesses, electrochemical ac and dc measurements in synthetic acid rain and chloride solutions C. CHIAVARIwere performed on the B6 binary alloy in comparison with an as cast bronze having a diVerent degree of purity. Moreover, to perform thin layer activation (T L A) measurements of thickness loss, a suitable radio nuclide 65Zn (t 1/2 =244 days) was produced on B6 specimens by a high energy proton beam. Artificial weathering experiments have been carried out by exposing activated and non-activated B6 specimens: to selected pollutants including NOx and SO 2 at diVerent concentrations to simulate urban and industrial atmospheres; in a cyclic salt spray cabinet to investigate the eVects of marine environments; to basic (NH 4 ) 2 SO 4 solutions reproducing the aggressiveness of ammonia containing wet deposits. At the end of each test, the B6 corrosion rates obtained by weight loss determinations have been compared with those arising from the T L A method. Finally, the nature and microstructure of the surface oxidation products were investigated.BCJ/1887

Composition and electrochemical properties of natural patinas of outdoor bronze monuments

“…As for evidence, the green traces of copper salts very often observed on basements of outdoor monuments are the results of an important leaching of bronze surfaces directly exposed to rainfalls. Numerous investigations have been conducted to understand the corrosion processes and patinas formation on copper and bronze [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. It has often been assumed that bronze corrosion in atmosphere reacts similarly as for pure copper one.…”

Assessment of the interphase behaviour of two bronze alloys in archaeological soil

“…Patina formation and the corrosion of ancient bronze objects in aqueous environments have been studied by multiple techniques, in various kinds of solutions and with various approaches [1][2][3][4][5][6][7][8][9][10], yet there are few detailed descriptions of the corrosion mechanism in soil. According to Geilmann, (cited by Scott [10]), the formation of patinas in burial is ascribed to oxygen and carbon dioxide present in the environmental context (as for example in humus or porous sandy soils).…”

Early stages of copper corrosion behaviour in a Tunisian soil

“…The first corrosion products that normally form on copper could be Cu(OH) copper surface and the more stable Cu 2 O [53]. The singular behaviour exhibited at [X] ¼ 0.5 kg/L is probably due to the establishment of the equilibrium (3) characterized by:…”

“…To confirm the proposed mechanisms, electrochemical characterizations were conducted on archaeological [19,26,[33][34][35][36] and modern materials [37][38][39][40][41][42][43][44][45][46][47][48][49]. However, all these investigations were made in aqueous media simulating the burying environments.…”